Abstract
The aqueous extracts ofHibiscus calyphyllus(HcA),Hibiscus micranthus(HmA), andHibiscus deflersii(HdA) growing in Saudi Arabia did not receive enough attention in phytochemical and biological studies. This inspired the authors to investigate the phytochemicals of these extracts for the first time using UPLC-ESI-MS/MS in negative and positive ionization modes. The analysis afforded the tentative identification of 103 compounds including phenolic compounds, flavonoids, and anthocyanins. Moreover,in vitroevaluations of their cytotoxic, antioxidant, antidiabetic, and antiobesity activities were carried out. The results showed that aqueous extract ofHibiscus calyphyllushad the highest activity as an antioxidant agent (SC50 = 111 +/- 1.5 mu g/mL) compared with ascorbic acid (SC50 = 14.2 +/- 0.5 mu g/mL). MTT assay was used to evaluate cytotoxic activity compared to cisplatin.Hibiscus deflersiishowed the most potent cytotoxic effect against A-549 (human lung carcinoma) with IC50 = 50 +/- 5.1 mu g/mL, andHibiscus micranthusshowed a close effect with IC50 = 60.4 +/- 1.7 mu g/mL.Hibiscus micranthusshowed the most potent effect on HCT-116 (human colon carcinoma) with IC50 = 56 +/- 1.9 mu g/mL compared with cisplatin (IC50 = 7.53 +/- 3.8 mu g/mL). HcA and HdA extracts showed weak cytotoxic activity against A-549 and HCT-116 cell lines compared to the other extracts. Eventually,Hibiscus deflersiishowed astonishing antidiabetic (IC50 = 56 +/- 1.9 mu g/mL) and antiobesity (IC50 = 95.45 +/- 1.9 mu g/mL) activities usingin vitro alpha-amylase inhibitory assay (compared with acarbose (IC50 = 34.71 +/- 0.7 mu g/mL)) and pancreatic lipase inhibitory assay (compared with orlistat (IC50 = 23.8 +/- 0.7 mu g/mL)), respectively. In conclusion, these findings are regarded as the first vision of the phytochemical constituents and biological activities of differentHibiscusaqueous extracts.Hibiscus deflersiiaqueous extract might be a hopeful origin of functional constituents with anticancer (on A-549 cell line), antidiabetic, and antiobesity activities. It might be a natural alternative remedy and nutritional policy for diabetes and obesity treatment without negative side effects. Isolation of the bioactive phytochemicals from the aqueous extracts of aerial parts ofHibiscus calyphyllus,Hibiscus micranthus, andHibiscus deflersiiand estimation of their biological effects are recommended in further studies.